Electronics integrated within a tire or other product offer potential advantages such as asset tracking and measurement of physical parameters as, for example, temperature and pressure. Often many of these systems rely on a wireless data link to communicate with an information system outside of the vehicle. Such information systems may include, as non-limiting examples, on-board computer systems, drive-by interrogators, or hand-held interrogators. In addition, the types of data communicated over such wireless data links are wide and varied and include such as not only the previously mentioned temperature and pressure but also other physical parameters such as tire rotation speed as well as data corresponding to manufacturing data and a host of other information. What ever the type of data transmitted, the wireless data link requires an antenna to be attached to the electronics in the tire. If the electronics and/or antenna are adhered to the tire rubber, flexing of the tire, either due to the tire building process or normal use can cause the antenna to separate from the electronics due to cracking, breaking, or fatigue.
The present invention primarily concerns physical factors such as mechanical stress leading to fatigue, which in turn can cause a circuit malfunction by physically breaking or weakening a specific part of the circuit. A typical location for such malfunction is at or near the point of connection of a wire, lead, or other conductor to an electrical circuit. In circumstances where the wire and the connected-to circuit may move or rotate relative to one another, the wire may incur a concentration of mechanical stress and/or fatigue at or near the point of connection to the circuit. Mechanical stresses such as repeated bending or twisting, for example, can lead to a weakening of the wire until a break occurs.
FIG. 1 provides an example of the problem addressed. In FIG. 1, lead 20 is connected to a printed circuit board 22 by a soldered connection 24. As lead 20 is twisted (as illustrated by arrow A), repeatedly bent (as illustrated by arrows B and C), or placed into tension or compression (arrow D), a concentration of stress occurs at or near the point of connection 26. Over time, as lead 20 is exposed to repeated mechanical cycles that provide for this concentration of stress, lead 20 may eventually weaken due to repeated deformation or cyclical movement. As a result, lead 20 will likely suffer a fatigue failure (or break) either at or near point of connection 26.